Week 2: Methods, strings and lists/12b. Letter triangle

Write a program that asks the user to enter a string.
The program will then print a triangle of letters corresponding to the string, as shown in the sample printouts below.


Example output:
Give a string: hello
h
he
hel
hell
hello




import java.util.Random;
import java.util.Scanner;



public class Test{
    public static void main(String[] args){
        final Random r = new Random();
        
        
        //ADD
        Scanner reader= new Scanner(System.in);
        System.out.print("Give a string: ");
        String user_str = String.valueOf(reader.nextLine());

        int wordLastIdx = user_str.length() - 1;
        for (int i = 0; i <= wordLastIdx; i++) {
            System.out.println(user_str.substring(0, i+1));
        }
                
       
    }
}






Testing with input abcdef
Give a string: abcdef
a
ab
abc
abcd
abcde
abcdef

Testing with input hi
Give a string: hi
h
hi

Testing with input xxxxx
Give a string: xxxxx
x
xx
xxx
xxxx
xxxxx

Testing with input goodevening
Give a string: goodevening
g
go
goo
good
goode
goodev
goodeve
goodeven
goodeveni
goodevenin
goodevening